Conventionally, fiber sheets are generally molded in order to fit them to certain shapes for various applications. As such molding methods, a heat press method, in which a pair of molds are used to mold a fiber sheet by the action of heat and pressure, or a cold press method, in which a pair of molds are used to mold a pre-heated fiber sheet by the action of pressure, are known.
In the case of molding by the former, i.e., the heat press method, the present applicant proposed “a fiber sheet for molding, characterized by being made of a fiber base material containing latent crimpable fibers of which crimps are expressed” (Patent literature 1) in order to improve the followability of the fiber sheet to the shape of the molds. However, since this fiber sheet for molding is poor in sound absorbing properties, in order to obtain sound absorbing properties, it is necessary to laminate it with a base material mat having good sound absorbing properties, or to use an adhesive resin film as an adhesive layer for adhering it to the base material mat. However, in the case of the former, i.e., laminating it with the base material mat having good sound absorbing properties, there is a problem in that the base material mat is limited, and that it is poor in versatility. In the case of the latter, i.e., using the adhesive resin film, regardless of the fact that it contains latent crimpable fibers of which crimps are expressed in order to improve the followability to the shape of the molds, there is a problem in that, since the adhesive resin film is difficult to stretch, a large amount of force is needed during molding, and if the molding is completed, there is another problem in that, since the adhesive resin film has low air permeability and it is difficult for the air to escape during molding, wrinkles are likely to occur.
Further, the present applicant proposed “a surface material for molding, characterized by consisting of a nonwoven fabric containing latent crimpable fibers of which crimps are expressed, wherein air permeability is 5 to 20 (cm3/cm2·s), and an extension at a load of 10 N in at least one direction is 50 mm or more” (Patent literature 2). Such a surface material for molding is actually produced by heating and pressing a crimp-expressing fiber web containing latent crimpable fibers, of which crimps are expressed. However, in order to achieve such a low air permeability, it is necessary to relatively strongly heat and press the web, and therefore, there is a problem in that the bulk of the surface material for molding is crushed to become paper-like, and that wrinkles are likely to occur when deep-drawing is carried out.